Photosensitive resin composition, production method for cured relief pattern using it, and semiconductor device

ABSTRACT

According to the present invention, there is provided: a photosensitive resin composition comprising a polyamide resin having a specific structure, a photosensitive agent, and a compound having at least two sulfonate ester groups; a production method for a cured relief pattern using the photosensitive resin composition; and a semiconductor device containing the cured relief pattern formed according to the production method.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a positive, high heat-resistantphotosensitive resin composition usable for surface protective film andinterlayer insulating film in semiconductor devices and for interlayerinsulating film in display devices, to a production method for aheat-resistant, cured relief pattern using the positive, highheat-resistant photosensitive resin composition, and to a semiconductordevice containing the relief pattern.

2. Description of the Related Art

For surface protective film and interlayer insulating film insemiconductor devices, used is polyimide resin that has excellent heatresistance, electric properties and mechanical properties. The polyimideresin is, at present, supplied generally as a photosensitive polyimideprecursor composition; and this is applied onto a support, and thenpatterned, developed and processed for thermal imidation, therebyreadily forming a surface protective film, an interlayer insulating filmor the like in a semiconductor device; and the composition ischaracterized in that the process with it may be greatly shortened ascompared with a conventional non-photosensitive polyimide precursorcomposition.

However, the photosensitive polyimide precursor composition requires alarge quantity of an organic solvent such as N-methyl-2-pyrrolidone asthe developer in the development step, and in view of the recentincrease in environmental problems, an organic solvent-free method isdesired. Given that situation, recently, various proposals of aheat-resistant photosensitive resin material developable with an aqueousalkali solution like photoresist have been made.

Above all, recently, a method of using a PBO precursor composition,which is prepared by mixing an aqueous alkali solution-solublehydroxypolyamide, such as polybenzoxazole (PBO) precursor with anoptically-active ingredient such as a photosensitive diazoquinonecompound, as a positive photosensitive resin composition has come toattract special attention.

The development mechanism of the positive photosensitive resin is asfollows: A non-exposed photosensitive diazoquinone compound is insolublein an aqueous alkali solution, but after exposed to light, thephotosensitive diazoquinone compound undergoes chemical change to be anindenecarboxylic acid compound and becomes soluble in an aqueous alkalisolution. Based on the dissolution speed difference between the exposedpart and the non-exposed part, only the non-exposed part may form arelief pattern (for example, see JP-A-56-27140).

On the other hand, as a technique of separating the photosensitivityfrom the insoluble function of the non-exposed part, in the field ofsemiconductor photoresists, much employed is a chemicalamplification-type photosensitive composition of such that it generatesa catalytic amount of an acid through exposure to light, and then in thesubsequent heating process, the alkali-insoluble group in thecomposition is converted into an alkali-soluble group through chemicalreaction with the acid having been generated through the photoexposureand acting as a catalyst. Also in the technical field of the presentinvention, such a chemical amplification-type photosensitive compositionis disclosed (for example, see JP-T-2002-526793).

However, with the recent development of semiconductor technology, finerpattern fabrication is required and it is also required to lower thecuring temperature after patterning.

In particular, when the curing temperature is lowered, it is known thatthermal benzoxazole cyclization is hardly promoted. Regarding thisproblem, for example, it has already been reported that the problemcould be solved by addition of sulfonic acid or a sulfate compound (forexample see JP-A-2006-010781 and JP-A-2006-126809). However, it has beenknown that even these compounds are still insufficient.

Specifically, a material having excellent lithography performance (filmretentiveness, resolution performance), capable of curing at a lowtemperature not higher than 250° C. and having heat resistance has notas yet been found out.

SUMMARY OF THE INVENTION

The invention is to provide a photosensitive resin composition havinglithography performance comparable to that of semiconductor photoresistand capable of forming a cured relief pattern having excellent heatresistance through low-temperature curing; a production method for acured relief pattern using the photosensitive resin composition; and asemiconductor device containing the cured relief pattern formedaccording to the production method.

The present inventors have found that the above-mentioned problems canbe solved by a photosensitive resin composition comprising a polyamideresin having a specific structure and a photosensitive agent, and inaddition to these, further containing a sulfonate ester compound havinga specific structure, and have completed the present invention.Specifically, the subject matter of the invention is attained by thefollowing:

-   [1] A photosensitive resin composition comprising:-   (A) a polyamide resin comprising a structure represented by general    formula (1);-   (B) a photosensitive agent; and-   (C) a sulfonate ester represented by general formula (2),

wherein R₁ represents a 2-valent to 8-valent organic group having atleast 2 carbon atoms; R₂ represents a 2-valent to 6-valent organic grouphaving at least 2 carbon atoms;

G and R₃ each independently represents a hydrogen atom or an organicgroup having from 1 to 20 carbon atoms; m indicates an integer of from 0to 2; p and q each independently indicates an integer of from 0 to 4,provided that p+q>0,

wherein A represents an h-valent linking group;

R₀ represents an alkyl group, an aryl group, an aralkyl group or acyclic alkyl group;

R₀′ represents a hydrogen atom, an alkyl group or an aralkyl group; and

h indicates from 2 to 8.

-   The photosensitive resin composition of the above [1], wherein the    polyamide resin contains a structure represented by general formula    (3):

wherein Ar₁ represents a group selected from a 4-valent aromatic groupand a 4-valent heterocyclic group; Ar₃ represents a group selected froma 2-valent aromatic group, a 2-valent heterocyclic group, a 2-valentaliphatic group and a 2-valent alicyclic group; G has the same meaningas in formula (1).

The photosensitive resin composition of the above [2], wherein thepolyamide resin further comprises a structure represented by generalformula (4):

wherein Ar₂ represents a group selected from a 2-valent aromatic group,a 2-valent heterocyclic group, a 2-valent alicyclic group, and a2-valent aliphatic group which may have silicon ; Ar₃ represents a groupselected from a 2-valent aromatic group, a 2-valent heterocyclic group,a 2-valent aliphatic group and a 2-valent alicyclic group.

-   [4] The photosensitive resin composition of the above [2], wherein a    protective group represented by the group G in formula (3) is a    group that decomposes by action of an acid to generate an    alkali-soluble group.-   [5] The photosensitive resin composition of any of the above [1] to    [4], further comprising (D) a compound containing an alkoxymethyl    group or an acyloxymethyl group.-   [6] The photosensitive resin composition of any of the above [1] to    [5], further comprising (E) an adhesion promoter.-   [7] A method for producing a cured relief pattern, the method    comprising: forming a layer of the photosensitive resin composition    of any of the above [1] to [6], on a semiconductor substrate;    exposing the layer to any of light rays, electron rays and ion rays    via a mask so as to form an exposed part; removing the exposed part    with an aqueous alkali developer to form an relief pattern; and    heating the relief pattern so as to form the cured relief pattern.-   [8] A semiconductor device comprising the cured relief pattern    obtained in the production method of above [7].

DETAILED DESCRIPTION OF THE INVENTION

The invention is described in detail hereinunder.

The photosensitive resin composition of the invention comprises (A) apolyamide resin having a structure represented by the following generalformula (1), (B) a photosensitive agent, and (C) a sulfonate esterrepresented by the following general formula (2).

(1) Polyamide Resin:

The polyamide resin in the invention has a structure represented by thefollowing general formula (1):

wherein R₁ represents a 2-valent to 8-valent organic group having atleast 2 carbon atoms; R₂ represents a 2-valent to 6-valent organic grouphaving at least 2 carbon atoms;G and R₃ each independently represent any of a hydrogen atom or anorganic group having from 1 to 20 carbon atoms; m indicates an integerof from 0 to 2; p and q each independently indicate an integer of from 0to 4, provided that p+q>0.

In particular, the polyamide resin in the invention is preferably apolyamide resin containing a structure represented by the followinggeneral formula (3) and general formula (4):

wherein Ar₁ represents a group selected from a 4-valent aromatic groupand a 4-valent heterocyclic group; Ar₂ represents a group selected froma 2-valent aromatic group, a 2-valent heterocyclic group, a 2-valentalicyclic group, and a 2-valent aliphatic group which may have silicon;Ar₃represents a group selected from a 2-valent aromatic group, a2-valent heterocyclic group, a 2-valent aliphatic group and a 2-valentalicyclic group; G has the same meaning as in formula (1).

In the above, the number of the structures represented by formula (3) inone molecule of the resin is from 5 to 1000, and the number of thestructures represented by formula (4) in one molecule of the resin isfrom 0 to 900.

The resin having the structure represented by formula (1) generally hasa degree of polymerization of from 10 to 1000, and may be produced, forexample, by reacting the following monomers (A), (B) and (C) in thepresence of a base or a dehydrating condensing agent.

In the formulae, Ar1, Ar2 and Ar3 are as previously defined in theabove; W represents —Cl, —OR, or —OH, in which R represents an alkylgroup (preferably having from 1 to 10 carbon atoms), a cycloalkyl group(preferably having from 3 to 10 carbon atoms), or an aryl group(preferably having from 6 to 10 carbon atoms), for example, including—CH₃, —C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, t-C₄H₉, cyclohexyl, phenyl,p-chlorophenyl, p-nitrophenyl.

The ratio of [(A)+(B)]/(C) is generally between about 0.9 and 1.1. Themonomer (A) accounts for from about 10 to 100 mol % of [(A)+(B)]; andthe monomer (B) accounts for from about 0 to 90 mol % of [(A)+(B)].

The bisaminophenol having a structure of (A) Ar₁(NH₂)₂(OH)₂ includes,for example, 3,3′-dihydroxybenzidine,3,3′-diamino-4,4′-dihydroxybiphenyl,4,4′-diamino-3,3′-dihydroxybiphenyl, 3,3′-diamino-4,4′-dihydroxydiphenylsulfone, 4,4′-diamino-3,3′-dihydroxydiphenyl sulfone,bis(3-amino-4-hydroxyphenyl)methane,2,2-bis(3-amino-4-hydroxyphenyl)propane,2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane,2,2-bis(4-amino-3-hydroxyphenyl)hexafluoropropane,bis(4-amino-3-hydroxyphenyl)methane,2,2-bis(4-amino-3-hydroxyphenyl)propane,4,4′-diamino-3,3′-dihydroxybenzophenone,3,3′-diamino-4,4′-dihydroxybenzophenone,4,4′-diamino-3,3′-dihydroxydiphenyl ether,3,3′-diamino-4,4′-dihydroxydiphenyl ether,1,4-diamino-2,5-dihydroxybenzene, 1,3-diamino-2,4-dihydroxybenzene,1,3-diamino-4,6-dihydroxybenzene. One or more of these bisaminophenolsmay be used either singly or as combined.

Of the bisaminophenols having the structure (A), especially preferredare those where Ar₁ is an aromatic group selected from the following:

In the formulae, X₁ represents —O—, —S—, —C(CF₃)₂—, —CH₂—, —SO₂—,—NHCO—. In the above structures, —OH and —NH₂ in the structure (A) bondin the ortho-position (adjacent position) to each other.

The diamine having a structure (B) Ar₂(NH₂)₂ includes an aromaticdiamine and a siliconediamine.

Of those, the aromatic diamine includes, for example,m-phenylenediamine, p-phenylenediamine, 2,4-tolylenediamine,3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether,4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfone,4,4′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone,3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,3,4′-diaminodiphenyl methane, 4,4′-diaminodiphenyl sulfide,3,3′-diaminodiphenyl ketone, 4,4′-diaminodiphenyl ketone,3,4′-diaminodiphenyl ketone, 2,2′-bis(4-aminophenyl)propane,2,2′-bis(4-aminophenyl)hexafluoropropane,1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene,1,4-bis(4-aminophenoxy)benzene,4-methyl-2,4-bis(4-aminophenyl)-1-pentene,4-methyl-2,4-bis(4-aminophenyl)-2-pentene,1,4-bis(α,α-dimethyl-4-aminobenzyl)benzene, imino-di-p-phenylenediamine,1,5-diaminonaphthalene, 2,6-diaminonaphthalene,4-methyl-2,4-bis(4-aminophenyl)pentane, 5 (or6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, bis(p-aminophenyl)phosphine oxide, 4,4′-diaminoazobenzene, 4,4′-diaminodiphenylurea,4,4′-bis(4-aminophenoxy)biphenyl,2,2-bis[4-(4-aminophenoxy)phenyl]propane,2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane,2,2-bis[4-(3-aminophenoxy)phenyl]benzophenone,4,4′-bis(4-aminophenoxy)diphenyl sulfone,4,4′-bis[4-(α,α-dimethyl-4-aminobenzyl)phenoxy]diphenyl sulfone,4,4′-diaminobiphenyl, 4,4′-diaminobenzophenone, phenylindanediamine,3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl,o-toluidine sulfone, 2,2-bis(4-aminophenoxyphenyl)propane,bis(4-aminophenoxyphenyl) sulfone, bis(4-aminophenoxyphenyl)sulfide,1,4-(4-aminophenoxyphenyl)benzene, 1,3-(4-aminophenoxyphenyl)benzene,9,9-bis(4-aminophenyl)fluorenone, 4,4′-(3-aminophenoxy)diphenyl sulfone,4,4′-diaminobenzanilide, and compounds derived from those aromaticdiamine by substituting the hydrogen atom of the aromatic nucleustherein with at least one or atom selected from a group consisting of achlorine atom, a fluorine atom, a bromine atom, a methyl group, amethoxy group, a cyano group and a phenyl group.

A siliconediamine may be selected for increasing the adhesiveness tosubstrates, and its examples are bis(4-aminophenyl)dimethylsilane,bis(4-aminophenyl)tetramethylsiloxane,bis(4-aminophenyl)tetramethyldisiloxane,bis(γ-aminopropyl)tetramethyldisiloxane, 1,4-bis(γ-aminopropyldimethylsilyl)benzene,bis(4-aminobutyl)tetramethyldisiloxane, bis(γ-aminopropyl)tetraphenyldisiloxane.

As the siliconediamine, also mentioned is the following structure.

In the above, R₅ and R₆ each represent a divalent organic group, R₇ andR₈ each represent each represent monovalent organic group. The divalentorganic group represented by R₅ and R₆ is, for example, a linear orbranched alkylene group having from 1 to 20 carbon atoms, a phenylenegroup having from 6 to 20 carbon atoms or a divalent alicyclic grouphaving from 3 to 20 carbon atoms, which may have a substituent, and agroup to be formed by combining them. The monovalent organic grouprepresented by R₇ and R₈ is, for example, a linear or branched alkylgroup having from 1 to 20 carbon atoms or an aryl group having from 6 to20 carbon atoms, which may have a substituent.

More concretely, they include the following:

The alicyclic group preferably has from 3 to 20 carbon atoms, and morepreferably, it includes the following structures:

The compound having a structure (C) includes those in which Ar3 is anaromatic group, a heterocyclic group or an aliphatic group selected fromthe following groups.

Examples of the aromatic group and the heterocyclic group are mentionedbelow.

In the formulae, A represents a divalent group selected from a group of—CH₂—, —O—, —S—, —SO₂—, —CO—, —NHCO—, —C(CF₃)₂—.

The aliphatic group includes a linear, branched or cyclic divalentstructure having from 1 to 20 carbon atoms. More preferably, it is acyclic aliphatic group having from 3 to 15 carbon atoms, including thefollowing structures.

The group represented by Ar3 preferably has —COOR₃ as the substituent,in which R3 represents a hydrogen atom or an organic group having from 1to 20 carbon atoms.

From the viewpoint of the storability, the above resin is preferablyblocked at the terminal of the carboxyl group or the amino group.

For example, there may be mentioned structures represented by thefollowing general formulae:

In formula (4), the terminal group may be readily introduced by reactingthe terminal amino group with an acid anhydride or an acid chloride. Z₁represents a monovalent organic group bonding to the formula via acarbonyl group or a sulfonyl group; and the organic group represented byZ₁ preferably has at least one carboxyl group, ester group, alkenylgroup or alkynyl group. When the terminal group could be apolymerization point in heating for curing, then it is especiallypreferred as capable of improving the physical properties of the curedfilm.

Z₂ represents a monovalent organic group, and is preferably an arylgroup which may have a substituent. Preferably, the group has, as thesubstituent, at least one carboxyl group, ester group, alkenyl group oralkynyl group. When the terminal group could be a polymerization pointin heating for curing, then it is especially preferred as capable ofimproving the physical properties of the cured film.

Concretely, it is desirable that, after a polyamide resin (notcontaining Z₁) that could be the base having a structure represented byformula (1) and a structure represented by formula (3) has beenproduced, the terminal amino group in the polyamide resin is capped withan acid anhydride or an acid derivative capable of bonding thereto via acarbonyl group or a sulfonyl group, thereby giving an amide. Preferredexamples of the group represented by Z₁ are, for example, the following,to which, however, the invention should not be limited.

Of those, especially preferred are the groups selected from thefollowing. Two or more of these may be combined for use herein.

In case where the resin has a —COOR group on the carbon atom adjacent tothe carbon of the amido bond therein, the group may be imidated. In theinvention, the terminal group is preferably a group of the case. Theimidated terminal group structure includes, for example, the following:

In producing the resin having a terminal group represented by formula(5), a monofunctional amine (Z₂-NH₂) may be added to the monomers (A) to(C) and reacted with them.

Preferred terminal groups are the following structures.

Not specifically defined, the group G for protecting the hydroxyl groupin the above resin may be any organic group capable of protecting ahydroxyl group, and it may be a group capable of leaving through actionwith an acid or a group not leaving through action with an acid.

To the protecting reaction, for example, applicable is a reaction offorming an ether bond or an ester bond through etherification oresterification of a hydroxyl group-having resin with an alkyl halide oran acyl halide under a basic condition.

The protective group includes an alkyl group having from 1 to 20 carbonatoms (e.g., methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl,benzyl), an acyl group having from 1 to 10 carbon atoms (e.g., acetyl,propionyl, butyryl, octanoyl, benzoyl), an alkoxycarbonyl group havingfrom 2 to 10 carbon atoms (e.g., methoxycarbonyl, ethoxycarbonyl,t-butoxycarbonyl), a carbamoyl group having from 1 to 10 carbon atoms(e.g., N,N-dimethylcarbamoyl, N,N-diethylcarbamoyl,morpholin-4-ylcarbonyl).

Especially preferred are an alkylcarbonyl group, an alkylsulfonyl group,and a substituted carbamoyl group. The alkyl group shown herein is alinear, branched or cyclic alkyl group which has from 1 to 20 carbonatoms and may have a substituent.

Preferred substituents are a halogen atom, a hydroxyl group, a cyanogroup, a nitro group and a phenyl group. The heat stability of the resinmay be controlled by selecting the substituent on the carbon near to thecarbonyl group or the sulfonyl group or by changing the number of thecarbon atoms constituting the alkyl group.

Especially preferably, the alkylcarbonyl group is a methylcarbonylgroup, an ethylcarbonyl group, an n-propylcarbonyl group, ani-propylcarbonyl group, an n-butylcarbonyl group, an octylcarbonylgroup, a hexadecanylcarbonyl group, or a cyclohexylcarbonyl group.

Especially preferably, the alkylsulfonyl group is a methylsulfonylgroup, an ethylsulfonyl group, an n-propylsulfonyl group, ani-propylsulfonyl group, an n-butylsulfonyl group, an i-butylsulfonylgroup, an octylsulfonyl group, a hexadecanylsulfonyl group, or acyclohexylsulfonyl group.

The substituted carbamoyl group is represented by —CO—NH—R or—CO—N(—R)₂, in which R represents an aliphatic group, a substitutedaliphatic group, an aromatic group, a heteroaromatic group, asubstituted aromatic group or a substituted heteroaromatic group.Especially preferred is —CO—N(—R)₂ In this, the aliphatic group may havea cyclic structure of a branched structure. The number of the carbonatoms constituting the aliphatic group is preferably from 1 to 15, morepreferably from 1 to 10, most preferably from 1 to 6. The aliphaticgroup may have a substituent. Examples of the substituent are analiphatic group having from 1 to 4 carbon atoms, an alkoxy group havingfrom 1 to 4 carbon atoms, a cycloalkyl group having from 6 to 12 carbonatoms, a hydroxyl group, a carboxyl group, a cyano group, a nitro group.The number of the carbon atoms constituting the aromatic hydrocarbongroup is preferably from 6 to 18. The aromatic hydrocarbon group mayhave a substituent. Examples of the substituent may be the same as thoseof the substituent in the substituted aromatic group and the substitutedheteroaromatic group. The heterocyclic group preferably has a 5-memberedor 6-membered hetero ring. The hetero ring may be condensed with anyother hetero ring, aliphatic ring or aromatic ring. The hetero atom ofthe heterocyclic group is preferably a nitrogen atom, an oxygen atom ora sulfur atom. The heterocyclic group may have a substituent. Examplesof the substituent in the heterocyclic group may be the same as those ofthe substituent in the substituted aromatic group and the substitutedheteroaromatic group. Preferred examples of the substituted carbamoylgroup are an N,N-dimethylcarbamoyl group, an N,N-diethylcarbamoyl group,an N,N-dipropylcarbamoyl group, an N,N-dibutylcarbamoyl group, and anN,N-diphenylcarbamoyl group, to which, however, the invention should notbe limited.

As the protective group, more preferred is a group capable ofdecomposing through the action of an acid thereon to generate analkali-soluble group (hydroxyl group or carboxyl group)(acid-decomposing group), or a group capable of leaving through theaction of an acid thereon to generate a hydroxyl group on the side ofthe resin.

A preferred acid-decomposing group includes an acetal group and an estergroup represented by the following formulae:

In the above acetal group, R₁ represents an alkyl group having from 1 to4 carbon atoms; W represents a linear, branched or cyclic alkyl grouphaving from 1 to 10 carbon atoms; n indicates an integer of from 1 to 4.In the above acetal group, W is preferably a linear, branched or cyclicalkyl group having from 1 to 6 carbon atoms, and n is 1 or 2.

The acetal group includes, for example, the following structures.

In the formulae, R′, R″ and R′″ each independently represent an alkylgroup having at most 5 carbon atoms; X represents a divalent alkylenegroup having at least 3 (and preferably at most 20) carbon atoms(optionally having a side branch).

Specific examples of the acetal group are an alkoxyalkyl group such as amethoxymethyl group, an ethoxyethyl group; and a tetrahydropyranylgroup, a tetrahydrofuranyl group, an alkoxy-substitutedtetrahydropyranyl group, an alkoxy-substituted tetrahydrofuranyl group.

In the above ester group, R₂ independently represents a hydrogen atom oran alkyl group having from 1 to 10 carbon atoms; k indicates an integerof from 0 to 4; R₃ represents a branched or cyclic tertiary alkyl group.In the ester group, k is preferably 0 or 1. The number of the carbonatoms constituting R₃ preferably falls within a range of from 4 to 15,more preferably from 4 to 13. Specific examples of R₃ are a t-butylgroup, a t-amyl group, a 1-methylcyclopentyl group, a 1-ethylcyclopentylgroup, a 1-ethylcyclohexyl group.

The group that leaves though the action of an acid thereon furtherincludes an alkylsilyl group (preferably having from 1 to 20 carbonatoms, such as methylsilyl, ethylsilyl).

Preferably, the resin in the invention is one produced by protecting anon-protected resin not having G, of which the dissolution speed in anaqueous solution of 2.38% by mass of tetramethylammonium hydroxide(TMAH) (23° C.) is at least 0.1 μm/sec. Also preferably, the protectedresin is so controlled as to have a dissolution speed in an aqueous 2.38mas. % TMAH solution of at most 0.04 μm/sec.

Regarding the concrete degree of protection, it is desirable that from0.5 mol % to 50 mol % of all the hydroxyl groups in the resin areprotected, more preferably from 1 mol % to 40 mol %, even morepreferably from 3 mol % to 30 mol % thereof are protected. When thedegree of protection is too high, it is unfavorable as being problematicin that the adhesiveness to substrate may lower and the film massreduction during curing may increase.

(B) Photosensitive Agent:

The photosensitive agent in the invention is meant to indicate acompound that imparts the function of forming an image throughphotoexposure to the resin composition and/or a compound that triggersthe function. Concretely, it includes a compound capable of generatingan acid through photoexposure (photoacid generator), a photosensitivequinonediazide compound, dihydropyridine compound. Two or more of thesephotosensitive agents may be combined for use herein. For sensitivitycontrol, a sensitizer may be combined with the photosensitive agent.Preferably, the photosensitive agent is a photoacid generator and aphotosensitive naphthoquinonediazide.

(B1) Quinonediazide Photosensitive Agent:

An o-quinonediazide photosensitive agent may be obtained, for example,through condensation of an o-quinonediazide-sulfonyl chloride and ahydroxy compound and/or an amino compound in the presence of adehydrochlorinating agent.

The o-quinonediazide-sulfonyl chloride includes, for example,benzoquinone-1,2-diazide-4-sulfonyl chloride,naphthoquinone-1,2-diazide-5-sulfonyl chloride,naphthoquinone-1,2-diazide-4-sulfonyl chloride; but from the viewpointof the sensitivity, preferred is use ofnaphthoquinone-1,2-diazide-4-sulfonyl chloride.

The hydroxy compound includes, for example, hydroquinone, resorcinol,pyrogallol, bisphenol A, bis (4-hydroxyphenyl)methane,2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,3,4-trihydroxybenzophenone,2,3,4,4′-tetrahydroxybenzophenone, 2,2′,4,4′-tetrahydroxybenzophenone,2,3,4,2′,3′-pentahydroxybenzophenone,2,3,4,3′,4′,5′-hexahydroxybenzophenone,bis(2,3,4-trihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)propane,4b,5,9b,10-tetrahydro-1,3,6,8-tetrahydroxy-5,10-dimethylindeno[2,1-a]indene, tris(4-hydroxyphenyl)methane,tris(4-hydroxyphenyl)ethane.

The amino compound includes, for example, p-phenylenediamine,m-phenylenediamine, 4,4′-diaminodiphenyl ether,4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfone,4,4′-diaminodiphenyl sulfide, o-aminophenol, m-aminophenol,p-aminophenol, 3,3′-diamino-4,4′-dihydroxybiphenyl,44,′-diamino-3,3′-dihydroxybiphenyl,bis(3-amino-4-hydroxyphenyl)propane,bis(4-amino-3-hydroxyphenyl)propane,bis(3-amino-4-hydroxyphenyl)sulfone, bis(4-amino-3-hydroxyphenyl)sulfone,bis(3-amino-4-hydroxyphenyl)hexafluoropropane,bis(4-amino-3-hydroxyphenyl)hexafluoropropane.

O-quinonediazide-sulfonyl chloride and a hydroxy compound and/or anamino compound are preferably so blended that the total of the hydroxygroup and the amino group could be from 0.5 to 1 equivalent relative to1 mol of o-quinonediazide-sulfonyl chloride. A preferred ratio of thedehydrochlorinating and o-quinonediazide-sulfonyl chloride is within arange of from 1/1 to 1/0.9. The reaction temperature is preferably from0 to 40° C., and the reaction time is preferably from 1 to 24 hours.

The reaction solvent includes dioxane, 1,3-dioxolane, acetone, methylethyl ketone, tetrahydrofuran, chloroform, N-methylpyrrolidone. Thedehydrochlorinating agent includes sodium carbonate, sodium hydroxide,sodium hydrogencarbonate, potassium carbonate, potassium hydroxide,trimethylamine, triethylamine, pyridine, 4-dimethylaminopyridine.

In the photosensitive resin composition of the invention, the amount ofthe quinonediazide photosensitive agent is preferably from 5 to 50 partsby mass relative to 100 parts by mass of the total resin amount, morepreferably from 8 to 20 parts by mass, from the viewpoint of thedissolution speed difference between the exposed part and thenon-exposed part and the sensitivity latitude range.

The amount of the other photosensitive agent than the quinonediazidephotosensitive agent in the composition is preferably from 0.1 to 15parts by mass relative to 100 parts by mass of the total resin amount,more preferably from 0.5 to 10 parts by mass.

The quinonediazide photosensitive agent includes, for example, compoundsrepresented by the following structural formulae:

In these formulae, D independently represents any of H or the followinggroups:

However, in each compound, at least one D should be the above-mentionedquinonediazide group.

The quinonediazide photosensitive agent may be a commercial product ormay be produced according to a known method.

(B2) Photoacid Generator:

As the photoacid generator, herein usable are photocationicpolymerization photoinitiators, photoradical polymerizationphotoinitiators, photodecoloring agents of dyes, photodiscoloringagents, known compounds used in microresists that generate acids throughirradiation with active rays or radiations, and their mixtures. Thesemay be suitably selected for the photoacid generator.

For example, there may be mentioned diazonium salts, phosphonium salts,sulfonium salts, iodonium salts, imidosulfonates, oximesulfonates,diazosulfones, disulfones, o-nitrobenzyl sulfonates.

In addition, also usable herein are compounds produced by introducing agroup or a compound capable of generating an acid through irradiationwith active rays or radiations, into the main chain or the side branchof a resin, for example, the compounds described in U.S. Pat. No.3,849,137, German Patent 3914407, JP-A 63-26653, 55-164824, 62-69263,63-146038, 63-163452, 62-153853, 63-146029.

Further, the compounds that generate acid by light, described in U.S.Pat. No. 3,779,778 and EP 126,712 are also usable.

Of the compounds that generate acid through irradiation with active raysor radiation, preferred are those of the following general formulae(ZI), (ZII) and (ZIII):

In formula (ZI), R₂₀₁, R₂₀₂ and R₂₀₃ each independently represent anorganic group.

X⁻ represents a non-nucleophilic anion, and is preferably a sulfonateanion, a carbonate anion, a bis(alkylsulfonyl)amide anion, atris(alkylsulfonyl)methide anion, BF⁴⁻, PF⁶⁻ or SbF⁶⁻. Preferably, it isa carbon atom-containing organic anion.

Preferred organic anions are represented by the following generalformulae:

In the above formulae, R_(c1) represents an organic group.

The organic group of R_(c1) includes those having from 1 to 30 carbonatoms, and is preferably an alkyl group, cycloalkyl group or aryl groupwhich may be substituted, or a group formed by bonding these via asingle bond or via a linking group such as —O—, —CO₂—, —S—, —SO₃—,—SO₂N(Rd₁)-.

R_(d1) represents a hydrogen atom or an alkyl group.

R_(c3), R_(c4) and R_(c5) each independently represent an organic group.

The organic group for R_(c3), R_(c4) and R_(c5), referred to are thosementioned herein as a preferred organic group for R_(c1). Preferably,the organic group is a perfluoroalkyl group having from 1 to 4 carbonatoms.

R_(c3) and R_(c4) may bond to each other to form a ring.

The group to be formed by R_(c3) and R_(c4) bonding to each otherincludes an alkylene group, a cycloalkylene group, an arylene group.Preferred is a perfluoroalkylene group having from 2 to 4 carbon atoms.

The organic group for R_(c1) and R_(c3) to R_(c5) is preferably an alkylgroup substituted at the 1-position thereof with a fluorine atom or afluoroalkyl group, or a phenyl group substituted with a fluorine atom ora fluoroalkyl group. Having a fluorine atom or a fluoroalkyl group, theacidity of the acid generated by the compound through irradiation withlight may increase, and the sensitivity of the compound therebyincreases. R_(c3) and R_(c4) bonding to each other to form a ring isalso favorable since the acidity of the acid generated throughirradiation with light may increase and the sensitivity also increases.

In formula (ZI), the number of the carbon atoms constituting the organicgroup for R₂₀₁, R₂₀₂ and R₂₀₃ may be generally from 1 to 30, preferablyfrom 1 to 20.

Two of R₂₀₁ to R₂₀₃ may bond to each other to form a cyclic structure,which may have an oxygen atom, a sulfur atom, an ester bond, an amidebond or a carbonyl group in the ring. The group to be formed by two ofR₂₀₁ to R₂₀₃ bonding to each other may be an alkylene group (e.g.,butylene group, pentylene group).

Of the compounds that generate acid through irradiation with active raysor radiations, further preferred are those represented by the followinggeneral formulae (ZIV), (ZV) and (ZVI):

In formulae (ZIV) to (ZVI), Ar₃ and Ar₄ each independently represent anaryl group.

R₂₀₆ represents an alkyl group, a cycloalkyl group or an aryl group.

R_(207a) and R₂₀₈ each independently represent an alkyl group, acycloalkyl group, an aryl group or an electron-attracting group.R_(207a) is preferably an aryl group. R₂₀₈ is preferably anelectron-attracting group, more preferably a cyano group or afluoroalkyl group.

A represents an alkylene group, an alkenylene group or an arylene group.

In the photosensitive resin composition of the invention, the amount ofthe photoacid generator is preferably from 1 to 30 parts by massrelative to 100 parts by mass of the total resin amount, more preferablyfrom 3 to 20 parts by mass.

One or more such photoacid generators may be used either singly or ascombined. In case where two or more photoacid generators are combinedfor use herein, they are preferably so combined that they may generatetwo organic acids that differ in the number of all the constitutiveatoms except hydrogen atoms by at least 2.

Of the compounds that generate acid through irradiation with active raysor radiations, preferred examples are oximesulfonates (ZVI).

Specific examples of the preferred oximesulfonate compounds are thefollowing:

Triarylsulfonium salts having a specific substituent are also preferredexamples. Especially preferably, they are further combined with asensitizer.

If desired, two or more different types of these compounds may becombined for use herein.

As the specific substituent, at least one aryl group of thetriarylsulfonium salt is preferably substituted with anelectron-attracting group; and more preferably, the sum total of theHammet values of the substituents bonding to the aryl skeleton is largerthan 0.18.

The electron-attracting group as referred to herein means a substituenthaving a Hammet value (Hammet substituent constant p) of more than 0. Inthe invention, from the viewpoint of increasing the sensitivity of thecomposition, it is desirable that the sum total of the Hammet values ofthe substituents bonding to the aryl skeleton in the specific photoacidgenerator is at least 0.18, more preferably at least 0.46, even morepreferably at least 0.60.

The Hammet value indicates the degree of electron attractivity of thecation having a triarylsulfonium salt structure; and from the viewpointof increasing the sensitivity of the composition, the uppermost limit ofthe Hammet value is not specifically defined, but from the viewpoint ofthe reactivity and the stability of the composition, the Hammet value ispreferably from more than 0.46 to less than 4.0, more preferably frommore than 0. 50 to less than 3.5, even more preferably from more than0.60 to less than 3.0.

For the Hammet value in the invention, employed are the numerical datain Naoki Inamoto's Chemical Seminar 10, Hammet Rule—Structure andReactivity—(1983, issued by Maruzen).

The electron-attracting group to be introduced into the aryl skeletonincludes a trifluoromethyl group, a halogen atom, an ester group, asulfoxide group, a cyano group, an amide group, a carboxyl group, acarbonyl group. The Hammet values of these substituents are shown below.Trifluoromethyl group (—CF₃, m: 0.43, p; 0.54), halogen atom [e.g., —F(m: 0.34, p: 0.06), —Cl (m: 0.37, p: 0.23), —Br (m: 0.39, p; 0.23), —I(m: 0.35, p: 0.18)], ester group (e.g., —COCH₃, o: 0.37, p: 0.45),sulfoxide group (e.g., —SOCH₃, m: 0.52, p: 0.45), cyano group (—CN, m:0.56, p: 0.66), amide group (e.g., —NHCOCH₃, m: 0.21, p: 0.00), carboxylgroup (—COOH, m: 0.37, p: 0.45), carbonyl group (—CHO, m: 0.36, p:0.43). The parenthesized data mean the position of the substituentintroduced in the aryl skeleton, and the Hammet value thereof. (m: 0.50)means that the substituent introduced in the meta-position has a Hammetvalue of 0.50.

Of those substituents, preferred are nonionic substituents such ashalogen atom and a halogenoalkyl group, from the viewpoint of thehydrophilicity thereof; and more preferred is —CL from the viewpoint ofthe reactivity. From the viewpoint of the property of impartinghydrophilicity, preferred are —F, —CF₃, —Cl, —Br.

These substituents may be introduced into any one of the three arylskeletons of the triarylsulfonium salt structure, or may be introducedinto two or more of them. One or more substituents may be introducedinto each of the three aryl skeletons. In the invention, the sum totalof the Hammet values of the substituents introduced into these arylskeletons is preferably more than 0.18, more preferably more than 0,46.The number of the substituents to be introduced is not defined. Forexample, only one substituent having an especially large Hammet value(for example, having a Hammet value of more than 0.46 by itself) may beintroduced into only one aryl skeleton of the triarylsulfonium saltstructure. On the other hand, for example, plural substituents may beintroduced in such a manner that the total of their Hammet values couldbe more than 0.46.

As in the above, the Hammet value of the substituent varies, dependingon the position at which it is introduced; and therefore, the sum totalof the Hammet values in the specific photoacid generator of theinvention may be determined depending on the type of the substituent,the position at which the substituent is introduced and the number ofthe substituents introduced.

The Hammet value is represented generally at an m-position and ap-position; but in the invention, as an index of the electronattractivity, the substituent effect at an o-position is considered thesame as that at a p-position. The preferred position for substitution ism- and p-positions from the viewpoint of production, and a p-position isthe most preferred.

In the invention, preferred is a sulfonium salt tri- or moremulti-substituted with halogen atoms; and most preferred is a sulfoniumsalt tri-substituted with chlorines. Concretely, preferred is atriarylsulfonium salt structure in which every of the three arylskeletons is substituted with a halogen atom, more preferably with —Cl,even more preferably, with —Cl at the p-position.

The sulfonate anion that the triarylsulfonium salts in the compositionof the invention has includes, for example, an arylsulfonate anion, analkanesulfonate anion. Preferred is an anion substituted with a fluorineatom or a fluorine atom-having organic group.

The compound having a triarylsulfonium salt structure may be readilyproduced, for example, according to the methods described in J. Am.Chem. Soc., Vol. 112 (16), 1990, pp. 6004-6015; J. Org. Chem., 1988, pp.5571-5573; WO02/081439A1, or EP 1113005.

Specific examples are mentioned below, to which, however, the inventionshould not be limited.

(B3) Sensitizer:

A sensitizer capable of absorbing active rays or radiations to promotethe decomposition of the above-mentioned sulfonium salt may be added tothe composition of the invention. The sensitizer absorbs active rays orradiations to be in an electron-excited state. The sensitizer in anelectron-excited state is contacted with sulfonium, thereby causing theaction of electron transfer, energy transfer and heat generation.Accordingly, the polymerization initiator undergoes chemical reactionand is decomposed to generate a radical, an acid or a base.

Preferred examples of the sensitizer are those that belong to thefollowing compounds and have an absorption wavelength within a range offrom 350 nm to 450 nm.

Polynuclear aromatics (e.g., pyrene, perylene, triphenylene,anthracene), xanthenes (e.g., fluorescein, eosine, erythrosine,Rhodamine B, rose bengal), cyanines (e.g., thiacarbocyanine,oxacarbocyanine), merocyanines (e.g., merocyanine, carbomerocyanine),thiazines (e.g., thionin, methylene blue, toluidine blue), acridines(e.g., acridine orange, chloroflavin, acryflavin), anthraquinones (e.g.,anthraquinone), squaliums (e.g., squalium), coumarins (e.g.,7-diethylamino-4-methylcoumarin).

More preferred examples of the sensitizer are compounds represented bythe following formulae (IX) to (XIV):

In formula (IX), A¹ represents a sulfur atom or NR⁵⁰; R⁵⁰ represents analkyl group or an aryl group; L² represents a non-metallic atomic groupthat forms a basic nucleus of a dye along with the adjacent A¹ and theadjacent carbon atom; R⁵¹ and R⁵² each independently represent ahydrogen atom or a monovalent non-metallic atomic group; R⁵¹ and R⁵² maybond to each other to form an acidic nucleus of a dye; W represents anoxygen atom or a sulfur atom.

In formula (X), Ar¹ and Ar² each independently represent an aryl group,and they bond to each other via the bond of -L³-. In this, L³represents—O— or —S—. W has the same meaning as in formula (IX).

In formula (XI), A₂ represents a sulfur atom or NR⁵⁹; L4 represents anon-metallic atomic group that forms a basic nucleus of a dye along withthe adjacent A₂ and carbon atom; R⁵³, R⁵⁴, R⁵⁵, R⁵⁶, R⁵⁷ and R⁵⁸ eachindependently represent a monovalent non-metallic atomic group; R⁵⁹represents an alkyl group or an aryl group.

In formula (XII), A³ and A⁴each independently represent —S—, —NR⁶²— or—NR³—; R⁶² and R⁶³ each independently represent a substituted orunsubstituted alkyl group, or a substituted or unsubstituted aryl group;L⁵ and L⁶ each independently represent a non-metallic atomic group thatforms a basic nucleus of a dye along with the adjacent A³ or A⁴ and theadjacent carbon atom, R⁶⁰ and R⁶¹ each independently represent ahydrogen atom, or a monovalent non-metallic atomic group, or as takentogether, they may form an aliphatic or aromatic ring.

In formula (XIII), R⁶⁶ represents an aromatic ring or hetero ring whichmay have a substituent; A⁵ represents an oxygen atom, a sulfur atom or—NR⁶⁷—; R⁶⁴, R⁶⁵ and R⁶⁷ each independently represent a hydrogen atom ora monovalent non-metallic atomic group; R⁶⁷ and R⁶⁴, and R⁶⁵ and R⁶⁷ maybond to each other to form an aliphatic or aromatic ring.

In formula (XIV), R₆₈ and R₆₉ each independently represent a hydrogenatom or a monovalent non-metallic atomic group. R₇₀ and R₇₁ eachindependently represent a hydrogen atom or a monovalent non-metallicatomic group; n indicates an integer of from 0 to 4. When n is 2 ormore, R₇₀ and R₇₁ may bond to each other to form an aliphatic oraromatic ring.

As the sensitizer, especially preferred are anthracene derivatives.

Preferred examples of the compounds represented by formulae (IX) to(XIV) are the following (C-1) to (C-26), to which, however, theinvention should not be limited.

The above-mentioned sensitizers may be commercial products, or may beproduced according to known production methods.

The amount of the sensitizer to be added is preferably from 20 to 200parts by mass relative to 100 parts by mass of the photosensitive agent,more preferably from 30 to 150 parts by mass.

(C) Sulfonate Ester Compound:

A sulfonate ester is added to the composition of the invention.Preferably, a sulfonate ester represented by a general formula (2) isadded to attain high-level heat resistance.

The molecular weight of the sulfonate ester is generally from 230 to1000, preferably from 230 to 800.

A represents an h-valent linking group.

R₀ represents an alkyl group, an aryl group, an aralkyl group or acyclic alkyl group.

R₀′ represents a hydrogen atom, an alkyl group or an aralkyl group.

h indicates from 2 to 8.

The linking group for A includes, for example, an alkylene group (e.g.,methylene, ethylene, propylene), a cycloalkylene group (e.g.,cyclohexylene, cyclopentylene), an arylene group (e.g., 1,2-phenylene,1,3-phenylene, 1,4-phenylene, naphthylene), an ether group, a carbonylgroup, an ester group, an amide group, or a combination of these groups.The number of the carbon atoms constituting the linking group of A maybe from 1 to 15, preferably from 1 to 10, even more preferably from 1 to6.

The alkyl group for R₀ and R₀′ is generally an alkyl group having from 1to 20 carbon atoms, preferably an alkyl group having from 1 to 15 carbonatoms, more preferably an alkyl group having from 1 to 8 carbon atoms.Concretely, it includes methyl, ethyl, propyl, butyl, hexyl, octyl.

The aralkyl group for R₀ and R₀′ is an aralkyl group having from 7 to 25carbon atoms, preferably an aralkyl group having from 7 to 20 carbonatoms, more preferably an aralkyl group having from 7 to 15 carbonatoms. Concretely, it includes benzyl, tolylmethyl, mesitylmethyl,phenethyl.

The cyclic alkyl group for R₀ is generally a cyclic alkyl group havingfrom 3 to 20 carbon atoms, preferably a cyclic alkyl group having from 4to 20 carbon atoms, more preferably a cyclic alkyl group having from 5to 15 carbon atoms. Concretely, it includes cyclopentyl, cyclohexyl,norbornyl, camphoryl.

The linking group of A may further have a substituent. The substituentincludes an alkyl group (an alkyl group having from 1 to 10 carbonatoms, concretely methyl, ethyl, propyl, butyl, hexyl, octyl), anaralkyl group (an aralkyl group having from 7 to 15 carbon atoms,concretely benzyl, tolylmethyl, mesitylmethyl, phenethyl), an aryl group(an aryl group having from 6 to 10 carbon atoms, concretely phenyl,tolyl, xylyl, mesityl, naphthyl), an alkoxy group (the alkyl group maybe linear, branched or cyclic and may have from 1 to 10 carbon atoms,concretely, methoxy, ethoxy, linear or branched propoxy, linear orbranched butoxy, linear or branched pentoxy, cyclopentyloxy,cyclohexyloxy), an aryloxy group (an aryloxy group having from 6 to 10carbon atoms, concretely, phenoxy, tolyloxy, 1-naphthoxy), an alkylthiogroup (a linear, branched or cyclic alkylthio group having from 1 to 10carbon atoms, concretely, methylthio, ethylthio, linear or branchedpropylthio, cyclopentylthio, cyclohexylthio), an arylthio group (anarylthio group having from 6 to 10 carbon atoms, concretely phenylthio,tolylthio, 1-naphthylthio), an acyloxy group (an acyloxy group havingfrom 2 to 10 carbon atoms, concretely acetoxy, propanoyloxy,benzoyloxy), an alkoxycarbonyl group (an alkoxycarbonyl group havingfrom 1 to 10 carbon atoms, concretely methoxycarbonyl, ethoxycarbonyl,linear or branched propoxycarbonyl, cyclopentyloxycarbonyl,cyclohexyloxycarbonyl).

In formula (2), R₀ is preferably an alkyl group or an aryl group. R₀ ′is preferably a hydrogen atom or an alkyl group having from 1 to 6carbon atoms, more preferably a hydrogen atom, a methyl group or anethyl group, most preferably a hydrogen atom.

Specific examples of the sulfonate ester for use in the invention arethe following compounds, to which, however, the invention should not belimited.

The sulfonate ester for use in the invention may be commercial productsor may be produced according to known methods. The sulfonate ester foruse in the invention may be produced, for example, by reacting asulfinyl chloride or a sulfonic acid anhydride with a correspondingpolyalcohol under a basic condition.

The amount of the sulfonate ester to be added to the composition of theinvention is preferably from 1 to 20 parts by mass relative to 100 partsby mass of the whole resin in the composition, more preferably from 2 to15 parts by mass.

(D) Compound having alkoxymethyl group or acyloxymethyl group:

A compound having an alkoxymethyl group or an acyloxymethyl group may beadded to the composition of the invention. It is known that the compoundcan prevent a pattern from being fused or thermally shrunk duringcuring, not detracting from the lithography performance thereof.Unfortunately, however, when it is used in a low-temperature curingprocess, it has become known that the effect is insufficient though thereason is not clear, and the heat resistance of the cured film is notsufficient.

The present inventors have found that the combination of the compoundwith the above-mentioned sulfonate ester improves the heat resistanceand further the chemical resistance of the cured film.

The number of the carbon atoms constituting the alkoxymethyl group orthe acyloxymethyl group that the compound has is preferably from 2 to 5,more preferably 2 or 3. In particular, the alkoxymethyl preferably has 2carbon atoms; and the acyloxymethyl group preferably has 3 carbon atoms.

The total number of the alkoxymethyl group and the acyloxymethyl groupthat the compound has is preferably from 1 to 10, more preferably from 2to 8, even more preferably from 3 to 6.

The molecular weight of the compound is preferably at most 1500, morepreferably from 180 to 1200.

Typical structures of the compound having an alkoxymethyl group or anacyloxymethyl group in the invention are those in which an alkoxymethylgroup or an acyloxymethyl group directly bonds to the aromatic group, orbonds to N of the following urea structure, or bonds to triazine.

In the formulae, R represents an alkyl group having from 1 to 4 carbonatoms, or an acyl group having from 1 to 4 carbon atoms; R₁₀₁ and R₁₀₂each represent a monovalent organic group; R₁₀₁ and R₁₀₂, takentogether, may form a 5- to 8-membered ring.

The compounds in which an alkoxymethyl group or an acyloxymethyl groupdirectly bonds to the aromatic group are, for example, those representedby the following general formulae:

In the formulae, R₁₀₄ each independently represents an alkyl group or anacyl group; R₁₀₃ represents a hydrogen atom, an alkyl group, an alkenylgroup, an aryl group, an aralkyl group, or a group that decomposes bythe action of an acid to generate an alkali-soluble group.

R₁₀₅ each independently represents an alkyl group or an alkenyl group;a, b and c each independently indicate from 1 to 3; d is from 0 to 4;and e each independently indicates from 0 to 3.

X represents a single bond or a divalent organic group.

When X is a divalent organic group, the divalent organic group includesan alkylene group (e.g., methylene, ethylene, propylene), acycloalkylene group (e.g., cyclohexylene, cyclopentylene), an arylenegroup (e.g., 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, naphthylene),an ether group, a carbonyl group, an ester group, an amide group, and acombination of these groups. Preferably, X is a single bond or analkylene group.

The group of R₁₀₃ that decomposes by the action of an acid to generatean alkali-soluble group is a group that decomposes by the action of anacid to generate an alkali-soluble group such as a hydroxyl group or acarboxyl group to the resin side; and for example, it includes a groupthat leaves by the action of an acid, or —C (R⁴)₂—COOR⁵ (where R⁴ is ahydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and R⁵is a group that leaves by the action of an acid).

Regarding the group that decomposes by the action of an acid to generatean alkali-soluble group, when R₁₀₃ is a group that leaves by the actionof an acid, R₁₀₃ itself leaves by the action of an acid to generate —OH;or when R₁₀₃ is —C(R⁴)₂—COOR⁵, R⁵ leaves by the action of an acid togenerate —COOH.

Regarding the group that leaves by the action of an acid, referred toare those of the group G that leaves by the action of an acid in formula(1).

Examples of the compound having an alkoxymethyl group are mentionedbelow.

Examples of the compound having an acyloxymethyl group may be derivedfrom the compounds mentioned below by changing the alkoxymethyl grouptherein to an acyloxymethyl group.

The compound having an alkoxymethyl group or an acyloxymethyl group inthe molecule should not be limited to the compounds mentioned below.

The compounds having at least one of an alkoxymethyl group and anacyloxymethyl group may be commercial products or may be producedaccording to known production methods.

From the viewpoint of the heat resistance, preferred are compounds inwhich the alkoxymethyl group or an acyloxymethyl group directly bonds tothe aromatic group or to the triazine ring.

The amount of the compound to be added is preferably from 1 to 20 partsby weight relative to 100 parts by weight of the resin in thecomposition, more preferably from 3 to 15 parts by mass.

(E) Adhesion Promoter:

The positive photosensitive resin composition of the invention maycontain, as added thereto if desired, an adhesion promoter for impartingadhesiveness to the composition, such as an organic silicon compound, asilane coupling agent or a leveling agent. Examples of the compounds areγ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,vinyltriethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-methacryloxypropyltrimethoxysilane, urea-propyltriethoxysilane,tris(acetylacetonato) aluminium, acetylacetonato-aluminiumdiisopropylate. In case where the adhesion promoter is added, its amountis preferably from 0.1 to 20 parts by mass relative to 100 parts by massof the resin in the composition, more preferably from 0.5 to 10 parts byweight.

(F) Solvent:

Not specifically defined, the solvent may be any one capable ofdissolving the composition of the invention, but is preferably a solventhaving a boiling point not lower than 100° C. in order that the solventmay not evaporate more than required during coating and the compositionmay not form a solid deposit during coating.

Further, when a solvent remains in the cured film, the film could nothave good properties, and therefore, it is undesirable that a solventhaving a boiling point not lower than the curing temperature accountsfor at least 60% by mass of the whole solvent. As so mentioned in theabove, when the boiling point of the solvent is low, the composition mayform a solid deposit owing to the solvent evaporation during coating,and the solvent having a low boiling point is undesirable. Accordingly,preferred for use herein is a mixed solvent comprising a solvent (a)having a boiling point of from 100° C. to 170° C. and a solvent (b)having a boiling point of from 170° C. to 300° C.

The preferred solvent (a) includes propylene glycol monomethyl ether,propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate,methyl 3-methoxypropionate, ethyl lactate, 3-methoxybutanol,cyclohexanone. The preferred solvent (b) is an organic solvent,including N-methylpyrrolidone (NMP), γ-butyrolactone (GBL), propylenecarbonate, and their mixtures. However, the solvent for use in theinvention should not be limited to these. More preferred areγ-butyrolactone and propylene carbonate.

Preferably, the ratio by mass of (a) to (b) is within a range of from95/5 to 30/70, more preferably from 90/10 to 50/50.

(G) Patterning Method;

A method of forming a relief pattern by the use of the photosensitiveresin composition of the invention comprises (1) first applying thephotosensitive resin composition onto a suitable substrate, (2) thenbaking (pre-baking) the coated substrate, (3) exposing it to active raysor radiations, (4) developing it with an aqueous developer, and (5)curing it to give a cured relief pattern.

The coated and photoexposed substrate may be baked at a high temperatureprior to development. The developed substrate may be rinsed prior tocuring.

In the manner as above, the photosensitive resin composition of theinvention may be applied onto a semiconductor element so that thecoating film, after thermally cured, may have a predetermined thickness(for example, from 0.1 to 30 μm), then this may be pre-based,photoexposed, developed and thermally cured to produce a semiconductordevice.

A method of forming a relief pattern is described in more detailhereinunder.

The photosensitive resin composition of the invention is applied onto asuitable substrate. The substrate is, for example, a semiconductormaterial such as a silicon wafer, or a ceramic substrate, glass, metalor plastic. The coating method includes spraying, spin coating, offsetprinting, roller coating, screen printing, extrusion coating, meniscuscoating, curtain coating and dipping, to which, however, the inventionshould not be limited.

The coating film is pre-baked at an elevated temperature of from about70 to 120° C. for a few minutes to a half hour, depending on the coatingmethod. Subsequently, the obtained dry film is exposed to active rays orradiations via a mask in a desired pattern. As the active rays orradiations, usable are X rays, electron beams, UV rays, visible rays. Aradiation having a wavelength of 436 nm (g-line) or 365 nm (i-line) ismost preferred.

After the exposure to active rays or radiations, the coated and exposedsubstrate is advantageously heated at a temperature of from about 70 to120° C. The coated and exposed substrate may be heated for a shortperiod of time, generally for a few seconds to a few minutes, within theabove temperature range. In general, this step of this process istechnically referred to as post-exposure baking.

Next, the coating film may be developed with an aqueous developer,thereby forming a relief pattern. The aqueous developer may be an alkalisolution of an inorganic alkali (e.g., potassium hydroxide, sodiumhydroxide, aqueous ammonia), a primary amine (e.g., ethylamine,n-propylamine), a secondary amine (e.g., diethylamine,di-n-propylamine), a tertiary amine (e.g., triethylamine), analcoholamine (e.g., triethanolamine), a quaternary ammonium salt (e.g.,tetramethylammonium hydroxide, tetraethylammonium hydroxide), and theirmixture. A most preferred developer contains tetramethylammoniumhydroxide. In addition, a suitable amount of a surfactant may be addedto the developer. The development may be attained by dipping, spraying,paddling or the like method of development.

If desired, the relief pattern may be rinsed with deionized water. Next,in order to obtain a final pattern of resin of good heat resistance, therelief pattern is cured to form an oxazole ring. The curing may beattained by baking the substrate at a glass transition temperature Tg ofthe resin, in order that an oxazole ring capable of forming a finalpattern of good heat resistance could be formed. In general, patterningmay be attained through thermal curing at a temperature of from about300 to 400° C. However, the composition of the invention may form a filmhaving physical properties comparable to those of the film formed of aconventional composition, when thermally cured at a temperature lowerthan 300° C., more concretely at about 250° C.

EXAMPLES

The invention is described concretely with reference to the followingExamples, to which, however, the invention should not be limited.

[Preparation of Resin] (1) Production of Resin A-1:

293 g (0.8 mol) of hexafluoro-2,2-bis(3-amino-4-hydroxyphenyl)propane(by Nippon Kayaku), 126.6 g (1.6 mol) of pyridine and 1.2 kg ofN-methyl-2-pyrrolidone (NMP) were put into a 3-liter three-neck flask.This was stirred at room temperature, and then cooled in a dryice/acetone bath to −-25° C. A mixed solution of 73.9 g (0.364 mol) ofisophthaloyl chloride (by Tokyo Kasei), 107.4 g (0.364 mmol) of4,4′-oxybisbenzoyl chloride (obtained by converting 4,4′-oxybisbenzoicacid (by Aldrich) into its acid chloride according to a fixed method)and 700 g of NMP was dropwise added to the solution with keeping thereaction temperature between −20° C. and −30° C. After the completion ofthe addition, the obtained mixture was stirred at room temperature for16 hours. This was diluted with 2 L of acetone, and the resultingsolution was put into 50 L of deionized water kept stirred vigorously,and the precipitated white powder was collected by filtration. This waswashed with deionized water and a mixture of water/methanol (50/50).This was dried in vacuum at 40° C. for 24 hours to obtain the intendedresin (a-1). The yield was almost quantitative, and the number-averagemolecular weight of the resin (a-1) was 6.4×10³, as calculated in termsof polystyrene, and the degree of dispersion thereof was 2.1.

The resin (a-1) (400 g) was dissolved in PGMEA to prepare a 15%solution, to which was added 21 g of allyl chloroformate (by TokyoKasei), and stirred at room temperature for 3 hours. The obtainedreaction solution was washed with water, then 200 g of toluene was addedthereto, and the solvent was evaporated away at 60° C. to remove waterfrom the system by azeotropic dehydration, thereby giving a solutionhaving a solid concentration of 15%. Water in the system was 0.01%. 15 gof ethyl vinyl ether and 0.1 g of p-toluenesulfonic acid were addedthereto, and stirred at room temperature for 3 hours. Further, 15 g ofethyl vinyl ether and 0.1 g of p-toluenesulfonic acid were added, andstirred at room temperature for 3 hours. 20 g of triethylamine was addedto the obtained solution, and the reaction liquid was washed three timeswith water. Then, this was once diluted with 1 L of PGMEA added thereto,and thereafter the solvent was evaporated away at 50° C. to remove waterfrom the system by azeotropic dehydration, thereby giving a PGMEAsolution of resin A-1 having a solid concentration of 45%.

Its ¹H NMR confirmed that the degree of introduction of allylchloroformate was quantitative and that the degree of ethylacetalprotection of the hydroxyl group was 21 mol %.

(2) Production of Resin A-2:

A PGMEA solution (45%) of resin A-2 was produced in the same manner asin Production Example 1 and using the resin (a-1) produced in ProductionExample 1, for which, however, ethylmalonyl chloride (by Aldrich) wasused in place of allyl chloroformate. The number-average molecularweight of the resin A-2 was 6.5×10³, as calculated in terms ofpolystyrene, and the degree of dispersion thereof was 2.1. Its ¹H NMRconfirmed that the degree of introduction of ethylmalonyl chloride wasquantitative and that the degree of ethylacetal protection was 22 mol %.

(3) Production of Resin A-3:

A PGMEA solution (45%) of resin A-3 was produced in the same manner asin Production Example 1 and using the resin (a-1) produced in ProductionExample 1, for which, however, 5-norbornene-2,3-dicarboxylic acidanhydride (by Aldrich) was used in place of allyl chloroformate,pyridine was added during the reaction, the reaction temperature was 60°C. and the reaction time was 12 hours. The number-average molecularweight of the resin A-3 was 6.6×10³, as calculated in terms ofpolystyrene, and the degree of dispersion thereof was 2.2. Its ¹H NMRconfirmed that the degree of introduction of5-norbornene-2,3-dicarboxylic acid anhydride (imide form) wasquantitative and that the degree of ethylacetal protection was 20 mol %.

(4) Production of Resin A-4:

293 g (0.8 mol) of hexafluoro-2,2-bis(3-amino-4-hydroxyphenyl)propane(by Nippon Kayaku), 126.6 g (1.6 mol) of pyridine and 1.2 kg ofN-methyl-2-pyrrolidone (NMP) were put into a 3-liter three-neck flask.This was stirred at room temperature, and then cooled in a dryice/acetone bath to −25° C. A mixed solution of 44.7 g (0.22 mol) ofisophthaloyl chloride (by Tokyo Kasei), 147.6 g (0.5 mol) of4,4′-oxybisbenzoyl chloride (obtained by converting 4,4′-oxybisbenzoicacid (by Aldrich) into its acid chloride according to a fixed method)and 700 g of NMP was dropwise added to the solution with keeping thereaction temperature between −20° C. and −30° C. After the completion ofthe addition, the obtained mixture was stirred at room temperature for16 hours.

Next, a solution prepared by diluting 17 g (0.1 mol) of CKK-1 (by FUJIFILM) with 5 g of NMP was dropwise added to it, taking 10 minutes.Further, 50 g of pyridine was added, and stirred at 50° C. for 12 hours.The obtained solution was dropwise put into 2 L of distilled water,taking 1 hour, and the precipitated powder was collected by filtration.This was again put into 2 L of a solution of distilled water/methanol(1/1) to wash it, then collected by filtration and dried to obtain aresin A-4. The number-average molecular weight of the resin A-4 was6.1×10³, as calculated in terms of polystyrene, and the degree ofdispersion thereof was 2.0.

(5) Production of Resin A-5:

The above resin A-4 (400 g) was dissolved in PGMTA to prepare a 15%solution The solvent was evaporated away at 60° C. to remove water fromthe system by azeotropic dehydration, thereby giving a solution having asolid concentration of 20%. Water in the system was 0.01%. 20 g of butylvinyl ether and 0.1 g of p-toluenesulfonic acid were added thereto, andstirred at room temperature for 3 hours. Further, 20 g of butyl vinylether and 0.1 g of p-toluenesulfonic acid were added, and stirred atroom temperature for 3 hours. 20 g of triethylamine was added to theobtained solution, and the reaction liquid was washed three times withwater. Then, this was once diluted with 1 L of PGMEA added thereto, andthereafter the solvent was evaporated away at 60° C. to remove waterfrom the system by azeotropic dehydration, thereby giving a PGMEAsolution of resin A-5 having a solid concentration of 45%. Its ¹H NMRconfirmed that the degree of butylacetal protection of the hydroxylgroup was 17 mol %.

A-4 is a resin corresponding to A-5 with no acetal protection (OA=OH).

[Production of Photosensitive Agent] (1) Production of PhotosensitiveAgent (P-1):

21.6 g of a phenol compound mentioned below (BP-1) and 200 mL of1,4-dioxane were put into a three-neck flask, and dissolved to give auniform solution. Next, 27 g of 1,2-naphthoquinonediazide-4-sulfonylchloride was added and dissolved. The reaction chamber was cooled withice in water to 10° C., then 11.1 g of triethylamine was dropwise added,taking 1 hour. After the addition, this was stirred for 24 hours. Afterthe reaction, distilled water was added to dissolve the precipitatedsalt, stirred for 30 minutes, neutralized with diluted hydrochloricacid, and 1 L of distilled water was added for crystallization. Theprecipitated dark yellow powder was collected by filtration. Thefiltrate was again dissolved in 200 mL of dioxane, and this was thencrystallized in 1 L of distilled water. The precipitated matter wascollected by filtration, the collected matter washed with 1 L ofdistilled water, and then filtered to collect 39 g of the intended darkyellow powder product (P-1). The obtained (P-1) was analyzed withhigh-performance liquid chromatography (Waters' S1525), and the purityof the esterified product of the phenol compound (BP-1) was 98%(wavelength for detection, 254 nm).

(2) Production of Photosensitive Agent (P-2):

A photosensitive agent (P-2) was produced in the same manner as in theabove Production Example, for which, however, the phenol compound to beused was changed to the following (BP-2) and the amount1,2-naphthoquinonediazide-4-sulfonyl chloride was increased to twotimes. The obtained (P-2) was analyzed through high-performance liquidchromatography (Waters' S1525), and the purity of the esterified productof the phenol compound (BP-2) was 97.5% (wavelength for detection, 254nm).

[Preparation of Photosensitive Resin Composition]

The resin, the photosensitive agent, the solvent and the additives shownin Table 1, and the silane coupling agent shown below (2% by mass of allthe solid content) were mixed by stirring. Next, this was filteredthrough a cassette filter of PTFE (0.1 μm) to prepare a photosensitiveresin composition.

The photosensitive agent and the additives shown in Table 1 as theirabbreviations and the compounds used as other additives are mentionedbelow.

-   GBL: γ-butyrolactone-   PGMEA: propylene glycol monomethyl ether acetate-   EL: ethyl lactate

<Image Performance (Resolution Limit, Film Retentiveness)>

The prepared composition was applied onto a silicon wafer in a mode ofspin coating, and then baked on a hot plate at 120° C. for 4 minutes toform a film having a thickness of 7 μm. Using an i-line stepper, thisfilm was photoexposed via a pattern mask with repetitive 4-micron viaholes to a photoexposure level enough for reproduction of the 5-micronpattern.

Next, except for the compositions 4 and 5, the sample was heated at 90°C. for 3 minutes, and then statically developed for 60 seconds with anaqueous 2.38 mas. % TMAH solution applied onto the substrate. Then, thiswas rinsed with deionized water. Next, this was baked on a hot plate at100° C. for 2 minutes. After the development, the film thickness wasmeasured, and the film retentiveness was determined.

Film Retentiveness (%)=[(film thickness before development−filmthickness after development)×100]/(film thickness before development).

Further, the obtained pattern was analyzed with SEM to determine theresolution limit.

<Heat Resistance>

The prepared resin solution was applied onto a silicon wafer in a modeof spin coating, then baked on a hot plate at 120° C. for 4 minutes, andfurther heated in nitrogen at 250° C. for 60 minutes. The obtained filmwas analyzed for the thermal mass reduction in TGA (the film was heatedfrom 30° C. to 400° C. at a heating speed of 10° C./min to determine thefilm mass reduction by the heating).

<Chemical Resistance>

The prepared resin solution was applied onto a silicon wafer in a modeof spin coating, then baked on a hot plate at 120° C. for minutes, andfurther heated in nitrogen at 250° C. for 30 minutes. The obtained filmwas peeled from the wafer, dipped in THF for 2 hours, then pulled up anddried, and the mass change before and after the dipping was computed.

Chemical Resistance (%)=[100×(film mass before dipping−film mass afterdipping)]/(film mass before dipping).

The test results are shown in Table 1.

TABLE 1 Resolving Film Heat Chemical Photosensitive Sulfonate MethylolPower Retentiveness Resistance Resistance Resin Solvent Agent esterCompound (μm) (%) (%) (%) Example 1 A-1 GBL P-3 C-1 D-1 2 95 4.8 95 110g  15 g 3 g 4 g 8 g 2 A-2 GBL P-3 C-2 D-2 2 95 4.8 90 110 g  12 g 3 g 4g 8 g PC  3 g 3 A-3 GBL P-3 C-3 D-3 2 95 5 90 110 g  15 g 3 g 4 g 8 g 4A-4 PGMEA P-1 C-4 D-4 2 85 5.3 95 50 g 60 g 7 g 4 g 8 g GBL 15 g 5 A-4PGMEA P-2 C-5 D-5 2 85 5.5 95 50 g 60 g 7 g 4 g 8 g GBL 15 g 6 A-5 GBLP-3 C-1 D-2 2 95 4.8 90 110 g  15 g 3 g 4 g 8 g 7 A-1 GBL P-1 C-4 D-5 295 4.8 95 110 g  15 g 2 g 4 g 7 g P-3 2 g 8 A-3 GBL P-3 C-1 D-1 2 95 4.696 110 g  15 g 3 g 4 g 4 g D-5 4 g 9 A-3 EL P-3 C-1 D-2 2 95 4.8 90 110g   5 g 3 g 4 g 8 g GBL 10 g 10  A-5 GBL P-3 C-1 D-2 2 95 4.8 96 110 g 15 g 3 g 4 g 8 g D-5 4 g 11  A-4 PGMEA P-3 C-4 2 85 5.7 — 50 g 60 g 3 g4 g GBL 15 g 12  A-4 PGMEA P-3 C-1 2 85 5.7 — 50 g 60 g 3 g 4 g GBL 15 g13  A-4 PGMEA P-3 C-1 D-2 2 85 5.9 88 50 g 60 g 3 g 2.5 g   8 g GBL 15 gComparative Example 1 A-4 PGMEA P-3 C-6 D-2 2 85 6.5 80 50 g 60 g 3 g 4g 8 g GBL 15 g 2 A-4 PGMEA P-3 C-7 D-2 2 85 6.5 80 50 g 60 g 3 g 4 g 8 gGBL 15 g 3 A-4 PGMEA P-3 C-6 2 85 7.3 — 50 g 60 g 3 g 4 g GBL 15 g 4 A-4PGMEA P-3 C-7 2 85 7.3 — 50 g 60 g 3 g 4 g GBL 15 g 5 A-4 PGMEA P-3 C-6D-2 2 85 6.8 80 50 g 60 g 3 g 8 g 8 g GBL 15 g

As in Table 1, it is known that the composition of the invention isexcellent in all the resolving power, the film retentiveness, the heatresistance and the chemical resistance.

According to the invention, there is provided a photosensitive resincomposition having excellent lithography performance and capable offorming a cured relief pattern excellent in heat resistance throughlow-temperature curing.

The entire disclosure of each and every foreign patent application fromwhich the benefit of foreign priority has been claimed in the presentapplication is incorporated herein by reference, as if fully set forth.

1. A photosensitive resin composition comprising: (A) a polyamide resincomprising a structure represented by general formula (1); (B) aphotosensitive agent; and (C) a sulfonate ester represented by generalformula (2),

wherein R₁ represents a 2-valent to 8-valent organic group having atleast 2 carbon atoms; R₂ represents a 2-valent to 6-valent organic grouphaving at least 2 carbon atoms; G and R₃ each independently represents ahydrogen atom or an organic group having from 1 to 20 carbon atoms; mindicates an integer of from 0 to 2; p and q each independentlyindicates an integer of from 0 to 4, provided that p+q>0,

wherein A represents an h-valent linking group; R₀ represents an alkylgroup, an aryl group, an aralkyl group or a cyclic alkyl group; R₀′represents a hydrogen atom, an alkyl group or an aralkyl group; and hindicates from 2 to
 8. 2. The photosensitive resin composition asclaimed in claim 1, wherein the polyamide resin comprises a structurerepresented by general formula (3):

wherein Ar₁ represents a group selected from a 4-valent aromatic groupand a 4-valent heterocyclic group; Ar₃ represents a group selected froma 2-valent aromatic group, a 2-valent heterocyclic group, a 2-valentaliphatic group and a 2-valent alicyclic group; G has the same meaningas in formula (1).
 3. The photosensitive resin composition as claimed inclaim 2, wherein the polyamide resin further comprises a structurerepresented by general formula (4):

wherein Ar₂ represents a group selected from a 2-valent aromatic group,a 2-valent heterocyclic group, a 2-valent alicyclic group, and a2-valent aliphatic group which may have silicon; Ar₃ represents a groupselected from a 2-valent aromatic group, a 2-valent heterocyclic group,a 2-valent aliphatic group and a 2-valent alicyclic group.
 4. Thephotosensitive resin composition as claimed in claim 2, wherein aprotective group represented by the group G in formula (3) is a groupthat decomposes by action of an acid to generate an alkali-solublegroup.
 5. The photosensitive resin composition as claimed in claim 1,further comprising (D) a compound containing an alkoxymethyl group or anacyloxymethyl group
 6. The photosensitive resin composition as claimedin claim 1, further comprising (E) an adhesion promoter.
 7. A method forproducing a cured relief pattern, the method comprising; forming a layerof the photosensitive resin composition as claimed in claim 1, on asemiconductor substrate; exposing the layer to any of light rays,electron rays and ion rays via a mask so as to form an exposed part;removing the exposed part with an aqueous alkali developer so as to forman relief pattern; and heating the relief pattern so as to form thecured relief pattern.
 8. A semiconductor device comprising the curedrelief pattern obtained in the production method as claimed in claim 7.